Lipase-catalysed synthesis of natural ethanol esters: Effect of water removal on enzyme reutilisation

Lipase-catalysed synthesis of ethanol esters using natural substrates is presented. Initial substrate concentrations, optimised through an experimental design, were 0.8mol dm-3 lauric acid and 0.58mol dm-3 ethanol, with an initial esterification rate (r0) of 17.13 mmol dm-3 min-1. Two different water removal systems were compared: a cooling exchanger in the reactor headspace and a vacuum-based system. The best results were obtained with the second system. After six consecutive operations with the same enzyme, no loss of activity was observed. The yields obtained in all the runs were greater than 90%. Using the same approach three different natural esters (ethyl laureate, ethyl myristate and ethyl palmitate) were synthesised at 0.9 dm3 scale. Similar results were obtained in all three cases, with chemical yields always being greater than 90%. (C) 2000 Society of Chemical Industry.